If `I_1` & `I_2` be the sizes of real images for two positions of a convex lens between object and screen, then the size of the object is

A real image formed by a convex lens is always-

If x_1 be the size of the magnified image and x_2 the size of the diminished image in Lens Displacement Method, then the size of the object is :

The ratio of the size of the image to the size of the object is called-

The image formed by any convex lens of an object placed between f and 2f will be-

If the object and image distance is 30 cm of a convex lense then its focal length is

An object is kept at a far off distance in front of a convex lens of focal length 15 cm. State the position of the image.

At what distance from a concave mirror an object should be placed to get an image half the size of the object?

A concave mirros forms a real image magnified two times. If both the object and the screen are moved a real image magnified three times of the object is formed. If the screen is moved through a distance of 25 cm , then determine the displacement of the object and focal lenght of the mirror.

A luminous object is separated from a screen by distance d. A convex lens is placed between the object and the screen such that it forms a distinct image on the screen. The maximum possible focal length of this convex lens is